"reduce the prevalence of" is a perfectly correct and usable phrase in written English.
You can use it when you want to discuss reducing the occurrence or extent of something. For example, "We need to reduce the prevalence of poverty in our society."
Local authorities have the best opportunity to reduce the prevalence of tobacco smoking in their boroughs.
Stronger leadership on the problem in Uganda and Senegal has helped to reduce the prevalence of infection in those countries.
Local councils across the country are introducing measures to reduce the prevalence of seagull attacks.
"Reduction of active smoking should automatically reduce the prevalence of second-hand smoke exposure," they added.
Such a change might also reduce the prevalence of another common complaint — namely, that "all the interesting people are in the other place".
Professor Kuhn raises another concern: lower search costs could reduce the prevalence of long-term implicit contracts, which tend to spread risks and reduce wage dispersion.
This paper adds to the body of evidence suggesting that using preventative strategies might reduce the prevalence of Alzheimer's disease and other dementias in society.
Recent research has established a package of interventions, costing around $100, that when implemented together would reduce the prevalence of undernutrition by 20%.
"Instead, it's feasible that a safe, inexpensive, and publicly accessible vitamin D supplement in at-risk groups may reduce the prevalence of this risk factor".
Immunisation against human papilloma virus could reduce the prevalence of cervical cancer.
Through the banning of subreddits which engaged in racism and fat-shaming, Reddit was able to reduce the prevalence of such behavior on the site.
